Deep Mafic Roots to Arc Volcanoes: Mafic Recharge and Differentiation of Basaltic Andesite at North Sister Volcano, Oregon Cascades

Magma evolution and ascent at volcanic arcs: constraining petrogenetic processes through rates and chronologies

Large Ra excesses in a number of mafic arc magmas, and geophysical observations of earthquake hypocenters locations, indicate that mafic melts can get transferred from source to surface within days to ~1 kyr. Decreasing Ra–Th disequilibria with increasing SiO2 in co-magmatic suites of individual arc volcanoes suggest that magma differentiation often occurs on timescales of a few thousand years ...

Mafic - Ultramafic Rock Studies

Pulsatory andesite lava flow at Bagana Volcano

[1] Using a time series of TerraSAR-X spaceborne radar images we have measured the pulsatory motion of an andesite lava flow over a 14-month period at Bagana Volcano, Papua New Guinea. Between October 2010 and December 2011, lava flowed continuously down the western flank of the volcano forming a 3 km-long blocky lava flow with a channel, levees, overflows and branches. We captured four success...

Are There Significant Hydrothermal Resources in the U.s. Part of the Cascade Range?

The Cascade Range is a geothermal dichotomy. On the one hand, it is an active volcanic arc above a subducting plate and is demonstrably an area of high heat flow. On the other hand, the distribution of hydrothermal manifestations compared to other volcanic arcs is sparse, and the hydrothermal outflow calculated from stream chemistry is low. Several large estimates of undiscovered geothermal res...

The subduction factory: How it operates in the evolving Earth

JULY 2005, GSA TODAY ABSTRACT The subduction factory processes raw materials such as oceanic sediments and oceanic crust and manufactures magmas and continental crust as products. Aqueous fluids, which are extracted from oceanic raw materials via dehydration reactions during subduction, dissolve particular elements and overprint such elements onto the mantle wedge to generate chemically distinc...